1. Field of the Invention
The present invention relates to a data processor, and more particularly to a data processor such as a microcomputer system, for example, which previously stores code data for sequentially reading and processing the same.
2. Description of the Prior Art
There have generally been a number of electronic devices which store externally inputted code data in memory devices such as RAMs and thereafter sequentially read the stored data from the memory device in the stage of execution/processing to execute some processing on the basis of each code data. For example, a microcomputer system comprises a keyboard for entering key code data, which are stored in a memory device thereafter read and processed by a microcomputer. Such microcomputer systems are widely applied to devices for public welfare.
The amount of such code data depends on the number of bits thereof. Namely, n-bit code data can assume 2.sup.n different states, and the amount of such data is 2.sup.n. For example, the amount of 4-bit code data is 2.sup.4 =16.
In a conventional electronic device, such an amount of data is increased by increasing the number of bits of processed code data. However, such a method requires extension of a hardware circuit, and hence the device is complicated in structure while its cost is increased. In particular, the storage capacity of the memory is unnecessarily increased.